the reason I ask is I had to order plugs (no where had them) and they came in as tr6 6078, however on the ngk site for the Lightning they are tr6 4177?

The plugs have a screw on cap and were packed each in a single box if that matters.

Thanks for any info.

 

I have the same question I can only get ngk tr6 with the part number 6078.. is 4177 an american number and 6078 canadian.

Anyone have any idea?

 

I looked at sparkplugs.com and they didnt show a 6078??

 

I actually changed my mind from tr6's and went with tr- 7ix. They cost me around $80 cdn.

The reason I went with the tr7- ix is because every time i compared the stock plugs to the tr6's using a number of different cross reference guides they all showed the tr6 = the factory plug.

 

I noticed that too, but there are a ****load of people running them on ported eatons and 4lb lowers with great success over many miles.

Good enough for me, I bought 8 TR6ix's (NGK 3689's) tonight.

 

Ok, I contacted NGK and ask them about the different part numbers and this is the reply I got...

"Eric,

You are entirely correct, they are exactly the same spark plugs, the only difference is in the packaging and because of this we have different “Stock Numbers” (the 6078 & 4177).

Spark Plug Technical Help
NGK Spark Plugs Canada Limited"

Well guess this means I'll be installing the new plugs this weekend!!